Potential regulation of linoleic acid and volatile organic compound contents in meat of chickens by PLCD1

Omega-3(linolenic acid(ALA),docosapentaenoic acid,eicosapentaenoic acid)and omega-6(linoleic acid(LA),arachidonic acid)polyunsaturated fatty acids are essential for health and normal physiological functioning in humans.Here we report a genome-wide association study(GWAS)on LA content in chicken meat.The 19 significant single nucleotide polymorphisms(SNPs)identified by the GWAS approach were annotated in VILL,PLCD1 and OXSR1 genes with highly polymorphic linkage blocks,and explained 4.5%of the phenotypic variation in the LA content.Specifically,the PLCD1 mRNA expression level was negatively correlated with the LA content,and significantly higher in chickens with low LA content than in those with high LA content.In addition,PLCD1 was found to be involved in metabolic pathways,etc.Furthermore,the LA content was correlated with volatile organic compounds(e.g.,octanal,etc.),but no relationship was found with intramuscular fat and triglycerides in chicken meat.The results indicated that there are key SNPs in PLCD1 that regulate the content of LA,and it has no significant effect on fat deposition,but may affect the content of volatile organic compounds(VOCs).

Transcriptome-based analysis of key genes and pathways affecting the linoleic acid content in chickens

Linoleic acid is an essential polyunsaturated fatty acid that cannot be synthesized by humans or animals themselves and can only be obtained externally.The amount of linoleic acid present has an impact on the quality and flavour of meat and indirectly affects consumer preference.However,the molecular mechanisms influencing the deposition of linoleic acid in organisms are not clear.As the molecular mechanisms of linoleic acid deposition are not well understood,to investigate the main effector genes affecting the linoleic acid content,this study aimed to screen for hub genes in slow-type yellow-feathered chickens by transcriptome sequencing(RNA-Seq)and weighted gene coexpression network analysis(WGCNA).We screened for candidate genes associated with the linoleic acid content in slow-type yellow-feathered broilers.A total of 399 Tiannong partridge chickens were slaughtered at 126 days of age,fatty acid levels were measured in pectoral muscle,and pectoral muscle tissue was collected for transcriptome sequencing.Transcriptome sequencing results were combined with phenotypes for WGCNA to screen for candidate genes.KEGG enrichment analysis was also performed on the genes that were significantly enriched in the modules with the highest correlation.A total of 13310 genes were identified after quality control of transcriptomic data from 399 pectoral muscle tissues.WGCNA was performed,and a total of 26 modules were obtained,eight of which were highly correlated with the linoleic acid content.Four key genes,namely,MDH2,ATP5B,RPL7A and PDGFRA,were screened according to the criteria|GS|>0.2 and|MM|>0.8.The functional enrichment results showed that the genes within the target modules were mainly enriched in metabolic pathways.In this study,a large-sample-size transcriptome analysis revealed that metabolic pathways play an important role in the regulation of the linoleic acid content in Tiannong partridge chickens,and MDH2,ATP5B,RPL7A and PDGFRA were screened as important candidate genes affecting the linoleic acid content.The results of this study provide a theoretical basis for selecting molecular markers and comprehensively understanding the molecular mechanism affecting the linoleic acid content in muscle,providing an important reference for the breeding of slow-type yellowfeathered broiler chickens.

Preparation of Conjugated Linoleic Acid of High Purity and Its Apparent Kinetic Characteristics During Formation

Conjugated linoleic acid (CLA) is a fatty acid with physiological activities and potential application prospect. This paper focuses on the method of synthesis of conjugated linoleic acid of high purity and the process line and conditions for its purification that can be used in large scale production. CLA of more than 95% purity was prepared by means of urea adduct purification and conjugation using safflower oil as material. The total recovery of the product adds up to more than 48%. The reactive kinetics about linoleic acid from sunflower oil converted into CLA was investigated, and its apparent kinetic model was also established, which can be used as a base for industrial designs.

Effect of cis-9,trans-11-conjugated linoleic acid on cell cycle of gastric adenocarcinoma cell line(SGC-7901)

AIM: To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B(1), D(1), p16(ink4a) and p21(cip/waf1) of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25, 50, 100 and 200 micromol.L(-1))of c 9, t 11-CLA for 24 and 48h, with a negative control (0.1% ethane). RESULTS: The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9, t11-CLA.SGC-7901 cells. Eight day after treatment with various concentrations of c9, t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 micromol.L, 24h) showed significantly less (3)H-TdR incorporation than that in the negative controls (P【0.05 and P【0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2-3.0%, 24h and 9.1-0.9% at 48h, respectively), Cyclin A (11.0-2.3%, 24h and 8.5-0.5%,48h), B(1) (4.8-1.8% at 24h and 5.5-0.6% at 48h)and D(1) (3.6-1.4% at 24h and 3.7%-0 at 48h) as compared with those in the negative controls(the expressions of PCNA, Cyclin A, B(1) and D(1) were 6.5% at 24h and 9.0% at 48h, 4.2% at 24h and 5.1% at 48h, 9.5% at 24h and 6.0% at 48h,respectively)(P【0.01), whereas the expressions of P16(ink4a) and P21(cip/waf1), cyclin-dependent kinases inhibitors(CDKI), were increased. CONCLUSION: The cell growth and proliferation of SGC-7901 cell is inhibited by c9, t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A,B(1) and D(1) and enhanced expressions of CDKI(P16(ink4a) and p21(cip/waf1)).

Preparation of Conjugated Linoleic Acid and Identification of Its Isomers

Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material. The purity of CLA and total recovery of the product was more than 95% and 48%, respectively. The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC) linked to mass spectrometry (MS) and Fourier transform infrared spectroscopy (FTIR). The total amount of the two main isomers (9cis, 11trons-and 10trans, 12cis-CLA) determined by GC was more than 90% of the product.

A Study on Anti-oxidative Activity of Soybean Peptideswith Linoleic Acid Peroxidation Systems

Soybean bioactive peptides（SBPs） were prepared from the isolated soybean protein by proteolysis with an alkaline protease, alcalase, at 50℃ and pH = 8.0. The dependence of hydrolysis time on hydrolysis degree and molecular weight distribution were examined. The hydrolysate was fractionated on a Sephadex G-25 column and the anti-oxidative activities of the fractions were detected by the method of pyrogallol auto-oxidation. The average chain length of soybean peptides that have anti-oxidative activity was estimated to be about 7. The anti-oxidative properties of the soy- bean peptide were also studied by using linoleic acid peroxidation systems. The optimal condition of the peroxidation system was set up, Vc/Cu^2 ＋ as the inducer at pH = 7.4 and 25 ℃. In addition, soybean peptides show higher antioxidative activity compared with GSH.

Linoleic acid metabolic pathway allows for an efficient increase of intramuscular fat content in pigs

Background: Intramuscular fat(IMF) content is a relevant trait for high-quality meat products such as dry-cured ham,but increasing IMF has the undesirable correlated effect of decreasing lean growth.Thus,there is a need to find selection criteria for IMF independent from lean growth.In pigs,the proportion of linoleic(C18:2) and arachidonic(C20:4) acids decline with fat deposition and therefore they can be considered as indicators of fatness.The aim of this research was to estimate the genetic variation for C18:2 and C20:4 in IMF and their genetic correlations with IMF and lean growth traits,with the objective to assess their potential as specific biomarkers of IMF.The analysis was conducted using a full-pedigreed Duroc resource line with 91,448 records of body weight and backfat thickness(BT) at 180 days of age and 1371 records of fatty acid composition in the muscle gluteus medius.Results: The heritability estimates for C18:2 and C20:4 in IMF,whether expressed in absolute(mg/g of muscle) or in relative(mg/g of fatty acid) terms,as well as for their ratio(C20:4/C18:2),were high(> 0.40),revealing that the C18:2 to C20:4 pathway is subjected to substantial genetic influence.Litter effects were not negligible,with values ranging from8% to 15% of the phenotypic variance.The genetic correlations of C18:2 and C20:4 with IMF and BT were negative(-0.75 to-0.66,for IMF,and-0.64 to-0.36,for BT),if expressed in relative values,but almost null(-0.04 to 0.07),if expressed in absolute values,except for C18:2 with IMF,which was highly positive(0.88).The ratio of C20:4 to C18:2 also displayed a stronger genetic correlation with IMF(-0.59) than with BT(-0.10).Conclusions: The amount of C18:2 in muscle can be used as an IMF-specific biomarker.Selection for the absolute amount of C18:2 is expected to deliver a similar response outcome as selection for IMF at restrained BT.Further genetic analysis of the C18:2 metabolic pathway may provide new insights into differential fat deposition among adipose tissues and on candidate genes for molecular markers targeting specifically for one of them.

Effect of Altering Linoleic Acid and Linolenic Acid Dietary Ratios on the Performance and Tissue Fatty Acid Profiles of Prawn, Macrobrachium rosenbergii （de Man 1879） Post Larvae

A 90-day experiment was conducted to investigate the effects of different dietary linoleic acid （LA; 18：2n-6） and linolenic acid ratios （LNA; 18：3n-3） on growth induces, feed utilization and tissue fatty acid profile of freshwater prawn, Macrobrachium rosenbergii post-larvae （PL）. The experiment was conducted in cubic indoor fiberglass tanks, each holding 700 L in triplicate. Post-larvae with an average weight of 20.8 ± 0.20 mg were stocked at 80 PL m2. Five experimental isocaloric （15.06 MJ kgl digestible energy）, and isonitrogenous （30.45% digestible protein） diets were formulated by blending of soybean oil and linseed oil to containing five dietary LA/LNA ratios （7.80, 2.75, 1.28, 0.65 and 0.30）. The highest survival values were recorded for prawn PL fed diet containing 0.65 LA/LAN ratios. Growth indices of PL significantly increased （P 〈 0.05） with decreased dietary LA/LAN ratios to 0.65. The same trend was observed for the highest （P ≤ 0.05） protein efficiency ratio, protein productive value, fat retention, energy retention and best feed conversion ratio. The total whole tissue polyunsaturated fatty acid composition of M. rosenbergii PL was dominated by LA followed by LAN. Post larvae fed the diets containing higher LA/LNA ratios showed a higher tissue LA/LNA ratio. The obtained findings revealed that fatty acid patterns ofM. rosenbergii PL were influenced by fatty acid profiles of diets. The diet containing 0.65 LA/LNA ratio is recommended to obtaining optimum growth performance and feed utilization for M. rosenbergii PL.

Linoleic Acid Activates GPR40/FFA1 and Phospholipase C to Increase [Ca^(2+)]_i Release and Insulin Secretion in Islet Beta-Cells

Objective To elucidate GPR40/FFA1 and its downstream signaling pathways in regulating insulin secretion. Methods GPR40/FFA1 expression was detected by immunofluorescence imaging. We employed linoleic acid (LA), a free fatty acid that has a high affinity to the rat GPR40, and examined its effect on cytosolic free calcium concentration ([Ca2+]i) in primary rat β-cells by Fluo-3 intensity under confocal microscopy recording. Downregulation of GPR40/FFA1 expression by antisense oligonucleotides was performed in pancreatic β-cells, and insulin secretion was assessed by enzyme-linked immunosorbent assay. Results LA acutely stimulated insulin secretion from primary cultured rat pancreatic islets. LA induced significant increase of [Ca2+]i in the presence of 5.6 mmol/L and 11.1 mmol/L glucose, which was reflected by increased Fluo-3 intensity under confocal microscopy recording. LA-stimulated increase in [Ca2+]i and insulin secretion were blocked by inhibition of GPR40/FFA1 expression in β-cells after GPR40/FFA1-specific antisense treatment. In addition, the inhibition of phospholipase C (PLC) activity by U73122, PLC inhibitor, also markedly inhibited the LA-induced [Ca2+]i increase. Conclusion LA activates GPR40/FFA1 and PLC to stimulate Ca2+ release, resulting in an increase in [Ca2+]i and insulin secretion in rat islet β-cells.

Differential effects of adulterated versus unadulterated forms of linoleic acid on cardiovascular health

According to the classic ＂diet-heart＂ hypothesis, high dietary intake of saturated fats and cholesterol combined with low intake of polyunsaturated fats can increase levels of serum cholesterol and lead to the development of atherogenic plaques and ultimately cardio- vascular diseases. Recently, the beneficial health effects of omega-6 polyunsaturated fatty acids, particularly linoleic acid （LA）, on cardiovascular health have been called into question with some scientists suggesting that consumption of LA should be reduced in Western countries. The focus of this critical review is on the controversy surrounding the effects of dietary intake of LA on cardiovascular health. Specifically, we critically examined the effects of both unadulterated and adulterated forms of LA on cardiovascular health outcomes based on findings from epidemiological studies and randomized controlled trials. Additionally, we address common concems surrounding dietary intake of LA regarding its relationship with arachidonic acid, the ratio of omega-6 to omega-3 fatty acids, and its relationship with inflammation. Our critical review indicates that unadulterated forms of LA are cardioprotective and should be consumed as part of a healthy diet. In contrast, abundant evidence now indicates that adulterated forms of LA, predominantly hydrogenated vegetable oils, are atherogenic and should not be considered part of a healthy diet. The ability to adulterate the natural omega-6 fatty acid, LA, has contributed to mixed findings regarding the effects of this fatty acid on cardiovascular health. Thus, it is critical that the source of LA be taken into account when drawing conclusions about the physiological effects of this fatty acid. The findings of the present review are in line with current dietary recommendations of the American Heart Association.

EFFECT OF CIS-9, TRANS-11-CONJUGATED LINOLEIC ACID ON CELL CYCLE OF MAMMARY ADENOCARCINOMA CELLS(MCF-7)

Objective: To determine the effect of cis-9, trans-1 1-conjugated linoleic acid on the cell cycle of mammary cancer cells (MCF-7) and the possible mechanism of the inhibitory effect of c9,t11-CLA. Methods: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B1, D1, p16ink4a and p21cip/waf1 of MCF-7 cells at various c9,t11-CLA concentrations (25μM, 50μM, 100μM and 200μM), at 24h and 48h. 96% ethand was used as negative control. Results: The cell growth and DNA synthesis of MCF-7 cells were inhibited by c9,t11-CLA. After treatment with various doses of c9,t11-CLA mentioned above for 8 days, the inhibition frequency was 27.18%, 35.43%, 91.05%, and 92.86%, respectively. Inhibitory effect of c9,t11-CLA on DNA synthesis (except for 25μM, 24h) was demonstrated by significantly less incorporation of 3H-TdR than the negative control (P<0.05 and P<0.01). To further investigate the influence of the cell cycle progression, we found that c9,t11-CLA may arrest the cell cycle of MCF-7 cells. Immunocytochemical staining demonstrated that incubation with different concentration of c9,t11-CLA at various times significantly decreased the expression of PCNA, Cyclin A, B1, D1 in MCF-7 cells compared to the negative control (P<0.01), whereas the expression of p16ink4a and p21cip/waf1, cyclin-dependent kinases inhibitors (CDKI), were increased. Conclusions: The cell growth and proliferation of MCF-7 cells is inhibited by c9,t11-CLA via blocking cell cycle, accompanying reduced expression of cyclin A, B1, D1 and enhanced expression of CDKI (p16ink4a and p21cip/waf1).

Qualitative and Quantitative Analysis of Linoleic Acid in Polygonati Rhizoma

Objective To explore the major compound in Polygonati Rhizoma(Huang Jing,黄精)for quality control.Methods The major compound was isolated and analyzed by liquid chromatography-mass spectrometry(LC-MS),and subsequently further identified by nuclear magnetic resonance(NMR).Thin layer chromatography(TLC)was optimized based on the previous methods reported in the Chinese Pharmacopeia(2015 edition).Results The major compound was isolated from the natural material and identified as linoleic acid.A high performance liquid chromatography(HPLC)method with robust linearity(R2=0.9997),specificity,precision,stability,repeatability and recovery was developed for linoleic acid determination.TLC chromatogram was improved significantly after optimization for qualitative analysis.Conclusions The optimized TLC method is practical and can be adopted for quality control of Polygonati Rhizoma(Huang Jing,黄精).The levels of linoleic acid vary between species of Polygonati Rhizoma(Huang Jing,黄精),with Polygonatum cyrtonema Hua(Jiang Xing Huang Jing,姜型黄精)showing the highest contents.This study provides valuable information for quality control of Polygonati Rhizoma(Huang Jing,黄精).

Concentration of linoleic acid from cottonseed oil by starch complexation

The extraction of linoleic acid from fatty acids(FA) of the cottonseed oil using starch–FA complexes was developed for the first time. We showed that starch can form inclusion complexes of different strengths with FA and that the different strengths stem from the differences in chain length, degree of unsaturation, and position of double bonds of FA. The optimal separation conditions were determined as follows: The inclusion temperature is 69 °C, the inclusion time is 30 min, the starch/FA mass ratio is 10:1, and the ratio of the volume of methanol–water solution and the mass of FA is 18:1. Compared to urea inclusion complexation, starch complexation has milder reaction temperature and shorter reaction time. Under these conditions, linoleic acid can be concentrated from 38.9% to 70.04% by one-off extraction. Moreover, the experimental results demonstrate the almost perfect reusability of starch. These results show that starch complexation is a promising method that can be used to obtain highly concentrated linoleic acid from cottonseed oil.

The Effect of Parity on Conjugated Linoleic Acid(CLA) Content in Milk Fat and CLA-Desaturase Index from Holstein Dairy Cows

The performance of lactating dairy cows and composition of the fatty acids in milk fat were measured to investigate the effect of parity on conjugated linoleic acid(CLA)in milk fat and△~9-desaturase indices from Holstein dairy cows.Milk samples of two hundred and thirty-five lactating Holstein dairy cows in north China were tested.In order to avoid possible confounding effects of diet and season,Holstein cows were fed a single diet and milk was sampled on the same day.The average content of cis-9,trans-11 CLA was 5.14 mg/g fatty acids in milk fat,varying between 1.5 and 10.5 mg/g fatty acids.The average content of cis-9,trans-11 CLA of primiparous cattle was 5.19 mg/g fatty acids in milk fat,while it was 5.11 mg/g fatty acids in multiparous animals,with no significant difference between them(P】0.05).There was a significant(P【0.05)difference between the△~9-desaturase index of cis-9 C14:l and cis-9 C16:l between primiparous and multiparous cattle but not(P】0.05)in the△~9-desaturase index of cis-9 C18:l and cis-9,trans-11 CLA.

Optimization of conjugated linoleic acid triglycerides via enzymatic esterification in no-solvent system

We compared four esterifiable enzymes. The lipase Novozym 435 possessed the highest activity for the conjugated linoleic acid esterification during the synthesis of triglycerides. The triglycerides were synthesized by esterification of glycerol and conjugated linoleic acid （CLA） in a no-solvent system using lipase catalysis. We investigated the effects of temperature, enzyme concentration, water content, and time on esterification. Enzyme and water concentrations of up to 1% of the total reaction volume and a system temperature of 60℃ proved optimal for esterification. Similarly, when the esterification was carried out for 24 h, the reaction ratio improved to 94.11%. The esterification rate of the rotating screen basket remained high （87.28%） when the enzyme was re-used for the 5th time. We evaluated the substrate selectivity of lipase （NOVO 435） and determined that this lipase prefers the 10,12-octadacadienoic acid to the 9,11-octadecadienoic acid.

Conjugated Linoleic Acid and Dietary Fats Differentially Affect Hepatic ACAT Activity and LDL-Cholesterol in Postweanling Pigs Fed Low-Fat Diets

ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.

ELASTICITY OF MONOLAYER OF LINOLEIC ACID AND ITS POLYMER

The dynamic elasticity of linoleic acid monolayer on a subphase of 10** minus **4mol/L TbCl//3 at various surface pressure has been measured by means of dynamic oscillation method in measuring the change of surface pressure caused by periodic compression-expansion cycles of the barrier. The elasticity of monolayer increases with increasing of surface pressure linearly. The linoleic acid polymer monolayer has been obtained under UV-irradiation in situ when keeping a constant surface pressure. But the elasticity of the resulting polymerized monolayer is even smaller than that of its corresponding monomer monolayer. The elasticity of the polymerized linoleic acid monolayer decreases with increasing polymerization time. The explanation based on entropy has been presented. (Author abstract) 10 Refs.

Effects of Conjugated Linoleic Acids on Proliferation and Differentiation of Rat Preadipocytes

Conjugated linoleic acids （CLAs） are a generic term for linoleic acid isomers and have a variety of biological functions. After rat preadi- pocytes were incubated in CLAs-supplemented media, their proliferation and differentiation were observed by the cell count and the oil red O stai- ning. The results showed that the CLAs at different concentrations inhibited proliferation of the rat preadipocytes in a time- and dose-dependent manner. And the CLAs greatly decreased intracellular lipid content in mature adipocytes. Moreover, lipogenesis was inhibited by the CLAs in a dose-dependent manner. Therefore, the CLAs inhibit the lipogenesis by reducing the number of preadipocytes and decreasing the intracellular lipid

Study on Microwave Preparation of Conjugated Linoleic Acid from Corn Germ Oil

[Objective] The optimal craft of preparing conjugated linoleic acid from corn germ oil by dint of microwave method was studied. [Meth- od] Microwave power, microwave mode of action, the amount of catalyst and solvent were selected for single-factor-experiment. Then, based on the single-factor-experiment, the catalyst and solvent amount, and microwave function time were chosen for orthogonal experiment so as to deter- mine the optimal craft of preparing CLA from corn germ oil. UV absorption spectra and infrared absorption spectrum were used to analyse the struc- tural features of natural corn germ oil and CLA. [Resalt] The optimal preparation condition was as follow： the catalyst was 0.6 times heavier than oil, solvent was 3 times heavier than oil weight, microwave worked for ten minutes. Under the optimal condition, CLA was 56.3% and conversion rate was 99.47 %. The results indicated that non-conjugated double bonds of linoleic acid can be isomerized and changed into conjugated double bonds under the conditions of microwave irradiation,[ Conduslon] The study provided a new way for the preparation of CLA.

Increasing Conjugated Linoleic Acid Content in Milk and Cheese after Supplementing a Blend of Crude Soybean Oil Sediment Combined with Fish Oil to Grazing Dairy Cows

The aim of the work was to improve the healthy value of milk and cheese fatty acids (FA) by feeding a mix of crude soybean oil sediment (CSOS) combined with fish oil (FO) to grazing dairy cows. The CSOS is a by-product commonly discarded after oil extraction containing 3.3% moisture, 6% total ash and 70.7% oil, locally available, comparatively economic and easy to mix with other feed ingredients. The experiment lasted 55 days from September 30th to November 23th 2018 and was carried out at the dairy farm “Gacef” provider of milk to the dairy industrial plant “Capilla Del Señor” (CDS) located at the Villa María City, Córdoba Province, Argentine. A herd of 80 multiparous Holstein cows producing 24 kg-1 milk·cow-1·day-1 was used. The cows grazed an alfalfa and an oat pasture that represented about 47% of total dry matter (DM) intake supplemented at 8.5 kg DM·cow-1·day-1 with a total mixed ration (TMR) composed (DM basis) by cracked corn grain (35.18%), whole plant corn silage (31.98%), pelletized soyben meal (17.99%), the CSOS supplement (13.85%) and FO (0.99%). The TMR was supplied by halves after each milking time in groupal feeders yielding 1.4 kg·cow-1·day-1 of the CSOS and 0.1 kg·cow-1·day-1 of FO. Before the start of lipid supplementation, milk samples (5) were obtained from the farm-tank representing the standar or reference milk (Ref-Milk). After 21 days of supplementary lipid supply, additional milk samples (5) were obtained representing the modified milk (Mod-Milk). Milk samples were analyzed for chemical composition and milk FA profile. At each time, sufficient quantities of both (Ref- and Mod-Milk) were collected for manufacturing six types of cheeses. The results were analyzed through the Student-T test for independent observations. Oil supplementation did not modify (P > 0.05) the chemical composition of milk. Concentration of butyric acid (C4:0) in milk was not affected (P < 0.858). Concentration of total saturated FA (SFAs) in Ref-Milk averaged 58.83 g 100 g-1 FA and was decreased to 49.67 g 100 g-1 FA in Mod-Milk (P < 0.0001). Monounsaturated FA (MUFAs) increased (P < 0.001) from 32.03 g 100 g-1 FA in Ref-Milk to 38.13 g 100 g-1 FA in Mod-Milk (+19.07%) whereas polyunsaturated FA (PUFAs) increased (+36.1%) from 4.71 to 6.41 (P < 0.004). The Mod-Milk showed a significant (P < 0.002) reduction (-15.3% or 5.9 g 100 g-1 FA) for the total concentration of the potentially atherogenic fraction of milk FA (C12:0 to C16:0). The atherogenic index (AI) also decreased (P < 0.012) from 1.98 in Ref-Milk to 1.42 in Mod-Milk (-28.4%). Concentration of vaccenic acid (VA, trans-11 C18:1) in Mod-Milk averaged 7.77 g 100 g-1 FA which represented a 162 % increase (P < 0.0001) over that observed in Ref-Milk (2.95 g 100 g-1). Concentration of conjugated linoleic acid (CLA, cis-9, trans-11 C18:2) in Ref-Milk averaged 1.47 g 100 g-1 FA and showed an important increase (P < 0.002) in the Mod-Milk (3.86 g 100 g-1 FA, +163%). The omega 6/3 ratio resulted lower (P < 0.012) in the Ref-Milk (2.28) compared to the Mod-Milk (2.83). Milk and cheese FA composition were highly correlated (R2 = 0.99, P < 0.0001). The Mod-Cheeses showed similar results in AI, total concentration of SFAs, MUFAs and PUFAs compared to the milk of origin. Differences in FA composition between the cheeses made with the Ref- and Mod-Milk were equivalent to those described for milks. It is concluded that supplementation with a blend of CSOS supplement and FO was an effective way to improve the healthy value of dairy products by reducing contents of SFAs, atherogenic FAs and the atherogenicity index with a concomitant increase in VA and CLA. Modifications induced in the Mod-Milk were recovered in the Mod-Cheeses. The results obtained may help to reduce saturated fat intake and fight or prevent incidence of non-communicable, cardiovascular and chronic diseases.